Closure means for pressure cookers



Oct. 21, 1952 w. A. WELDEN CLOSURE MEANS FOR PRESSURE COOKERS 3Sheqs-Sheet 1 Filed June 15, 1946 \v \\T gvgm Oct. 21, 1952 w. A. WELDEN,6

I CLOSURE MEANS FOR PRESSURE COOKERS Filed June 15, 1946 3 Sheets-Sheet2 H Inveniar:

- ZJZZiam dlWeZde-n Oct. 21, 1952 w. A. WELDEN CLOSURE MEANS FORPRESSURE COOKERS Fi led June 15, 1946 3 Sheets-Sheet 3 Raven/$0 2: ZWi/ZZw/am uiwezaen Patented Oct. 21, 1952 oLosUnE MEANS FOR PRESSURE'CO0KER S William A. Welden, Stamford, .Conn., assignor to Revere Copperand Brass IncorporaterLRome,

N. Y., a corporation of Maryland Application June 15 1946, Serial No.67'7,'043 Y My invention relates, to pressure cookers. vThe inventionhas among its objects a pressure cooker or the like with animprovedcover and improved attaching and packing means for said cover. Amongother objects of the invention is an-improved relief valve for apressure cooker or the like, and improved means for indicating when w adesiredsteampressure in a cooker or the like has been reached. The aboveand other objects of the invention, however, will be best understoodfrom the following description when read in the light of theaccompanying drawings of a preferred embodiment of the inventionselected for illustrative purposes, the scope of the invention beingmore particularly pointed out in the appended claims. I v f a In thedrawings:

Fig. l is-a vertical section of a pressure cooker on the line ll of Fig.3 with parts in elevation;

1A is a fragmentary section of the pressure cooker cover and gasket onthe line [-1 of'Fig.

3, corresponding to the portion of the-cover and gasket at th upper lefthand side, of Figfll on an enlarged scale;

, Fig. 1B is a fragmentary section on the line of Fig. 3, correspondingto the upper left hand corner of Fig. 1 on an enlarged scale; f v

Fig. 2 is a section on the line 2-2 of Fig. 13; Fig. 3 is a plan of thepressure cooker according-to Fi 1; Figs..4 and are fragmentary sectionson the lines 4 4 and 515 of Fig. 3 with the cover omitted;

Fig. G is a'fragmentary plan view, on an enlarged scale, of the cookeraccording to Figs. 1 and 3'with the cover omitted; H

Fig. 7 is a section on the line 1-| of Fig. 6;

Fig. 8 is a section on the line 8- of Fig.

Fig. 9 is a plan view, on an'enlarged scale, of the "relief valve andturbine rotor assembly" according'to Figs. 1 and 2;

Fig. 10 is a development of a section, on the line l0l0 of Fig. 9, ofthe turbine rotor;

Fig. 11 is a section, corresponding to Fig. 1, illustrating a step inthe operation of placing the cover of the pressure cooker on thecontainer portion thereof;

Fig..l2 is a section on the line |2-i2 of Fig. l;

and

Fig. 13 is a-bottom view, on an enlarged scale,

of the relief valve and turbine rotor assembly according to Figs. 1, 2,9 and 10.

Referring to the drawings, the pressure cooker illustrated comprises acontainer having a bot,- tom wall '1, and, integral with said wall,cylindrical side walls 3. The container is preferably {14 Claims. (01."220-40 formed of sheet metal, such assheet-stainless steel, by av,deep' drawin operation. As shown,

the sidewalls 3 adjacent the brim of the eon:-

t'ainer are formed to present an upwardly and a outwardly fiaringfr'ustoconical-portion 5.

; v Jlliecover I, which also preferably is-presse d from sheet metal, isprovided with a downwardly and :inwardly tapered annular edge flange 9adapted to be rotatably received by the annular flared portion 5 of thecontainer. As shown, the

cover adjacent its flangea is formed with aslight-f lydepressed annularportion indicated at II, this portion being connected to the flange by acurved annular-corner portion l3. For purposes here,- inafter describedthese two flared portions {are so designed that, when the cover is inplace on the container coaxially thereof, there is no lateral surface tosurface contact between those portions. To this end, and as bestillustrated in Fig. 113, a slight lateral clearanceis provided be.-tween the upper portion of the flange and the adjacent surface of theflared portion 5 of the 7 container, the flange to compensate for anypossible spring or bending thereof preferably having a slightly greatertaper than the portion 5 so that a somewhat wider clearance is providedbetween the flared portions adjacent the lower 7 edge'of the flange.

As shown, thecover carries a gasket l5 in the form ofa continuous ring,'orsplit ring with abutting ends, of yieldable compressible material,for example, vulcanized natural or synthetic rubber, suitablyplasticized Du Pont ny1on,or the like. The gasketillustrated is ofwedge-shaped cross-section, its upper edgeor base and its outer annularsurface being shaped to fit in the recess between interior sides'of thecover body, cover edge flange 9 and rounded corner l3, when sprung intoor otherwise inserted insaid recess. The gasket extends well below thelower edge .of the flange 9 to provide a portion i! (hereinaftersometimes termed the ap ex portion of the gasket) which extendsradiallyoutward beyond theuouter surface of said flange so as to adaptthe gasket 'rotatably to seaton the lower part of the interior surfaceof the'flaring annular portion 5 of the container. ,lt'willibeobservedthat the construction described is such that the gasket is removablysecured to the. cover, and that the pressure in the cooker isoperativeto force the body of the gasket against the adjacent surfaces of thecover, and the apex portion of thegasket tainer.- Also it will beobserved that the eon structio'n is such as to' permit the gasketto'iyield 3 and relieve any vacuum tended to be created in the cooker ifthe contents of the latter are allowed to cool while the cover is inposition and the pressure relief valve, hereinafter described, is notopened by the operator. Such vacuum, it will be understood, if permittedto be formed would cause explosion of vegetables, such "as peas, havingthin impervious skins.

Because of the clearance between the cover flange 9 and the flaredportion of the container, and the apex portion I! of the yieldablecompressible gasket projecting radially outward beyond the outer surfaceof theflange, the weight of the cover and parts carried by it causes theapex portion of the gasket 'about'its entire .periphery firmly toseat onthe portion 5'when the cover is initially placed on the container. Thispermits steam pressure to build up in the cooker when its contents areheated, which otherwise would not occur if the gasket were not initiallyfirmly seated about its entire periphery on the container portion 5.Were the parts so designed that the flange 3 would seat on the portion 5of the container when the cover "is initially applied, the weight of thecover would be taken off the gasket with relianceonly on the radialoutward resiliency of the apex portion of the gasket to cause seating ofthe latter on the portion 5, and, under such conditions, no assurancecould be had that the gasket would 'seat on said' portion about itsentire periphery.

Further, it is difficult to make the cover flange and flared portion 5of the container truly circular, or to maintain them as such when the*cooker'is put into use, with the result that if the 'lower'portion ofthe gasket did not project radially'beyond the outer surface of thecover flange, to prevent surface to surface contact of that flange withthe container portion 5, no assurance would be had that the metal tometal contact would continuously extend about the entire periphery ofthe flangepandtherefore no assurance that when the cover is initiallyapplied the gasket about its entire periphery would continuously contactwith the container.

As illustrated, the container at its .brim is provided with an inwardlyprojecting lip I9, which lip extends for about 180 of the angular extentof the flared portion '5 of the container, as clearly shown in Fig. 3.This lip .is so shaped as to' fit over and contact with "the edgeportion of the cover when the interior of the cooker is under pressure.Diametrically opposite thelip I9 the container at its brim is providedwithlan outwardly projecting lip 2|, the outer portion of which lip isdownturned, as indicated 'at 23, so that the lip in cross-section ishookshaped as clearly shown in Figs. 1 and 11. The outwardly projectinglip 2|, as clearly shown in Figs.'3 and 6, extends for a much lessangular extent of the cylindrical walls of the container than does theinwardly projecting lip l9.

As shown, the cover I at its upper side carries a plate 25 preferablyspot welded thereto, 'the' plate conforming to the upper surface of thebo'dyof the cover and having a portion 21 which projects outward beyondthe edge flange 9 of the cover. At the outer end of the portion 21theplate 25 is bent downward, as indicated at 29, this downturnedportion at its lower edge being bent upward and inward to form a hook 3!adapted to engage with the downturned portion 23 of the lip 2|.

l The cover of the cooker may be placed on and secured to the containerby tilting the cover and inserting a portion of its edge beneath the lipI9, as shown in Fig. 11, whereupon the cover may be rotated relative tothe container to bring the hook 3| on the cover wholly between adjacentends of the lips I9 and 2| on the container, and, as part of the samemovement, be brought into a horizontal position to cause the apexportion H of the gasket l5 to seat on the inner surface of the portion 5of the container. The cover so positioned may then be axially rotated onthe container to cause the hook 3! on the cover tomove under the lip 2|.The cover may be removed by movements the reverse of those describedwhen the pressure in the cooker is relieved. Preferably, a suitable stopis provided for limiting. the rotative movement of the cover on thecontainer for engaging the hook 3| with the lip 21,23. As shown, such astop is formed by providing one end of the lower edge of the downturnedportion 23 of the lip 21 with an inturned projection 32 (Figs. 6, 7 and8), which projection isso positionedas to lie in the path of movement ofthe'hook 3| when the "applied cover is rotatedto cause said hook tomoveunder the lip. I

.As best'shownin Figs. l'and 1B, the parts preferably are-so designed asto present, when the cover'is initially applied, a slight clearancebetween the cover and the container lip I9, and approximately the samedegree of clearance between the lower edge of the container lip 23 andthe facing surface of the hook 3l. As the pressurebuilds up the coverrises relative to the container to take up these clearances, the gasketmoving upward with the cover while maintaining the seal. Providing theseclearances insures that the cover, when initially applied to thecontainer, will not be forced toward the latter at localized points byfaulty engagement of the lip [9 with the cover, or faulty engagement ofthe lip '23 with the hook 3|,either of which, if it occurred, mightcause the gasket to fail to seat continuously'about its entire peripheryon the container when the cover isinitially applied. Such faultyengagement of the parts would be liable to occur, if the mentionedclearances were not provided, because of discrepancies in manufacture,or bending or denting of the parts when in use.

'For rotating the cover the same is conveniently provided with a handle33 attachedto the plate 25. As shown, the plate is struck'up to form anupwardly extending projection or lug 35 inclined toward the edge of thecover, the handle being provided onits side adjacent the plate 25 with arecess 31 receiving this projection, the projection fitting the opposedlateral walls 33 (Fig. 3) of therecess and its rear wall 4| (Fig. 1). Asfurther illustrated, the portion 21 of the plate 25 is perforated andcountersunk, as indicated at 43 (Figs. 1 and 12) for receiving the fiatfrustoconical head 45 of a nut having ashank portion .41 received in andfitting a recess 48 in the adjacent side of the handle 33.Screw-threadedly received by this nut is a screw 49 extending throughthe handle from its upper edge, so that the handle is secured to theportion 2! of the plate 25 as Well as secured to the projection 35.

As shown, the container portion of the cover is provided with a handle5! having a metallic shank 53 provided with ears fifi'preferably spotwelded to the side walls 3 of the container.

The cover at its center portion is shown as perforated and struck up toform downwardly converging. annular walls 51 surrounding an opening 59,the lower portion of said walls interiorly thereof forming asubstantially frusto-coni'cal valve seat 6t. Cooperating with this valveseat is a conical valve 63 which, as illustrated, is formed "as part ofa metallic disk-likewight 65, fromthe under surface of which latter thevalve projects downwardly axially thereof. The crosssectional area ofthe opening in 'thercover' at the valve seat is such with relation tothe downward gravitational effect of the weight that the latter willlift when a predetermined pressure is established inthe cooker say, forexample, pounds pressure per square inch. j

As illustrated, the disk-like weight 65 is provided with downwardlyconverging frusto-conical lateral walls Bl in which is formed acircumferential open groove 69. Received in this groove is the arcuateportion I I of a bail-like member having the arms 13 integral with saidarcuate portion,'the latter, as clearly illustrated in Fig. 3, having a.greater angular extent than 180 so that when the arcuate portion isreceived in the groove 69 the" weight will be secured to the bail-likemember. Preferably, the bail-like member is formed of about stiff wirefor making the arcuate portion of said member transversely resilient, sothat said arcuate portion will snap into the groove 69 when the underside of the weight is presented to said arcuate portion and pressedtoward it, and will snap from the groove when the weight is forced awayfrom it. The arms 13 or the baillike member, as shown, terminate inoutwardly bent trunnion portions 15 (Fig. 3) which are received in whatoperatively amounts to spaced perforatedears formed by the bentportionsl? ofv the plate 25, which latter portions when assembled with the cover1 form openings between them and the upper side of said cover. Thearcuate portion ll of the bail-like member has sufficient resiliency toenable the arms to be pressed inwardly toward each other far enough toinsert the trunnion portions of the arms into the openiijgs beneath theportions ll of the plate 25 prior to assembling the weight with thebail-like member. Preferably the arcuate portion H of the baillikefmember fits the groove 69 of theweight rather loosely so as to insureseating of the valve 63 on the valve seat 6 I, and to permit axialrotation of the valve so that given portions thereof will not alwaysseat on the same given portions of thevalve seat. It will be understoodthat different weights 65 may be substituted to cause the valve to openat different desired pressures.

As illustrated, carried by the weight 65 in closely adjacent relation tothe fiat upper side 19 thereof is a flat disk-likerotor'al, preferablyformed of light weight material as, for example,

molded Du Pont nylon. As shown (see Fig. 2), screw-threadecll'y receivedin, the upper side of the weight is a screw 83 having the'e'nla-rgeddiameter portion 85 providing a shoulder 81 bearing against the uppersurface of the weight. The rotor BI is rotatably mounted on thisenlarged diameter portion, and is retained thereon by the furtherenlarged diameter head 89 of the screw. p

'As best shown in Figs. 2 and 13, the weight 65 is formed'with passages9| which col1ectivelysurround the valve 63 in concentricrelationthereto, the inner sides. of those passages being prolohgationsof the conical surface of said valve. These passages, which are flaredoutwardly and down- Wardly on all sides, open on the upper side 19Of'the weight through arcuate ports 93 and open on the lower surface ofthe weight through arcuate ports 95.

w v I In alignment withthe ports9 3 the rotor BI is formed with a seriesof through 6 passages" 9T- separated from each "other: by partition's 99which,' as clearly shown by. Figs. 9 "and 10'," are inclined in such'way as to form vanes for causing" steam jets which p'assthrough the.openings 9'! to tend to spin'the rotor. I When the pressure in thecooker'reaches a predetermined value as,"for example, 15 pounds thevalve 53 will slightly open to permit escape of steamTrom the cooker.This steam will discharge through the opening between the conicalsurfaces of the valve and valve-seat-in the'form of aninvrt'dcon'ical's'heet and will be directed into the passagesill of the weight.Because of the opworoiyo'oovorgmg walls of these'p'a'ssages this steamwill be discharged through the arcuate ports 93 at theupper side of theweight inthe form of jets whichwill impinge against the in'-' clinedvanes 930f the rotor and set the latter n motion, thus indicating to theoperator that the desired predetermined pressure has been reached, whichis otherwise difiicult to determine because the slight; amount of steamescaping 'when the valve, opens is superheated and discharges into thehotatmosphere above the stove or cooker and thus inmany cases is almostinvisible. Because of the light weight of the rotor and the constructiondescribed'the rotor spins instantly uporrthe valveslightly opening. Thisspinning indicates to theoperator that the gas flame or other source ofheat forthecooker should be diminished to the extent that will just keepthe rotor spinning at a moderate'speed if it is desiredto continuecooking at the predetermined pressure, or dlIIliIl'". ished to such anextent that the rotor'does not spin at all'in cases where it isdesiredto perform the cooking operation insuch way that the food isheated. until the predetermined pressurelis reached. and is, then cookedat. a temperature somewhatles'sjthan that which corresponds to thepredetermined pressure. H

, Toavoid'the possibility of the creation of a dangerously. highpressure in' the cooker should the valve controlledcover opening .59become clogged with foocLthe cover may be provided with emergencypressure relief means. As shown, for this purpose the cover is formedwith an opening I 0 l into Which opening is sprung a plug: like memberformed of yieldable materiahsuch asrubber, this-memberv comprising ashank portion 103 received by the opening and, integrally carried byopposite ends of said shank portion, heads I 05, adapted to bear againstthe upper andunder surfaces of the cover. The inner head I05 is adaptedto be forced against the-under surface. of the-cover by the pressure ofthe steam in the cooker. so as normally to render the opening lfil steamtight, but upon the'pressure reaching too high a value that head willshear off or collapse and the plug will be ejected from the opening.

, It will be understood that within the scope of the appendedclaims'widedeviations may be made from. the form of the invention herein describedwithout departing from the spirit of the invention. l

, Iclaimz v,1..A pressur cooker having, in combination,

acontainer comprising side walls having aportionadjacentthe containerbrim presenting an gasket carried-bysaid cover presenting a portionadapted to seat on said interiorsurface below said exterior surface whensaid cover is placed on saidcontainer to cause said cover portion to beso received, and means for detachably securing the cover ,to, saidcontainer.

1-2. Acpressure cooker having, in combination, a containercomprisingside walls having a portion adjacent the container brim presenting aninterior upwardly and outwardly flaring surface angularly coextensivewith said walls; a cover having a portion presenting exterior andinterior downwardly and inwardly flaring surfaces-adjacent itsperipheral edge angularly coextensive with said edge, which coverportion is adapted to be laterally loosely received by said containerportion; a ring-like yieldable gasket carried by saidcover, which gaskethas a portion received in the recess between the under side of the coverbody and said interior flaring surface of said coverportion for securingsaid gasket to said cover, the gasket also having a depending edgeportion adapted to seat on said interior flaring surface of saidcontainer below said cover portion when. said cover is placed on saidcontainer to cause said cover portion to be so received; and means fordetachably securing said cover to said container.

.3. A pressure cooker having, in combination, a container having sidewalls formed to present, adjacent the container'brim a portionpresenting an interior upwardly and outwardly flaring surface angularlycoextensive with said brim; a cover provided with a downwardly andinwardly flaring endless edge flange adapted to be laterally looselyreceived by said container portion at the upper part of said outwardlyflaring surface, a ring-like yieldable gasket carried by said cover,said gasket having a portion received in the recess between the underside of the cover body and said edge flange for securing said gasket tosaid cover, the gasket having a depending edge portion adapted to seaton said flaring surface ofsaid container below said edge flange whenthe'latter is so received, and means for detachably securing said coverto said container.

4. A pressure cooker according to claim 3 in which the edge flange ofthe cover presents parallel inwardly and downwardly flaring peripheralendless surfaces, and the gasket is of wedgeshaped cross-section, thebase of the gasket being adapted t seat against the under side of thecover body, and its outer, side being adapted to seat against theinterior side of said flange with a portion of said outer side of thegasket extending below the lower edge of said flange and radiallyoutward of said flange for seating on the upwardly and outwardly flaringcontainer surface when said. flange is laterally'loosely received by thecontainer portion presenting such container surface.

5. A pressure cooker having, in combination, a container comprising sidewalls having a portionadjacent the container brim presenting an interiorupwardly and outwardly flaring surface angularly coextensive with saidwalls, a cover having a portion presenting an exterior downwardly andinwardly flaring endless surface, which cover portion is adapted to bereceived by said container portion, means for securing the cover, whichgasket is adapted slidably to contact with said outwardlyflaring surfacewhen said cover is so received whereby to-establish an initial sealbetween the cover andcontainer to permit pressure to build up in thecooker and permit such lost motion to be taken up without interruptingsuch seal as the pressure in the cooker builds up.

6. A pressure cooker having, in combination, a container having sidewalls presenting .a portion having an upwardly and outwardly flaringinterior surface adjacent the container brim, means forming an inwardlyprojecting lip on said container above said surface for part of theangular extent of said surface, means forming an outwardly projectinglip on said container for another part of the angular extent of saidsurface, a cover presenting a portion having an exterior downwardly andinwardly flaringsurface, which cover portion is adapted .to be removablyreceived by said container portion when an edge portion of the cover isinserted beneath said inwardly projecting lip, and securing meanscarried by the cover for cooperation with said outwardly projecting lipwhen the cover isso received.

7. A pressure cooker having, in combination, a container presenting anannular cover receiving portion adjacent the container brim, meansforming. an inwardly projecting lip on said container above said portionfor part of the angular extent of the latter, means forming an outward-1y projecting lip on said container for another part of the angularextent of said portion, a cover having a portion adapted to be rotatablyreceived within said container portion when an edge portion of the coveris inserted beneath said inwardly projecting lip, and securing means onthe cover adapted to move into cooperation with said outwardlyprojecting lip upon rotation of the cover when so received.

8. A pressure cooker according to claim 7 in which the securing means onthe cover is in the form of an outwardly projecting lip adapted to bemoved under the outwardly projecting lip on the container by rotation ofthe cover relative to the latter.

9. A pressure cooker according to claim 7 in which the inwardlyprojecting lip on the container has its ends substantially diametricallyopposite each other.

10. A pressure cooker, according to claim '7 in which the'securing meanson the cover is in the form of an outwardly projecting lip adapted to bemoved under the outwardly projecting lip on the container by rotation ofthe cover relativeto the latter, theinwardly projecting lip on thecontainerhaving its ends substantially diametrically opposite eachother.

11. A pressure cooker having, in combination, a container comprisingside walls presenting a cover receiving portion having an interiorupwardly and outwardly flaring annular interior surface adjacent thecontainer brim, means forming an inwardly projecting lip carried by saidside walls above said surface for part of the angular extent of thelatter, means forming an outwardly projecting lip carried by said sidewalls for another part of the angular extent of said surface, a coverhaving a depending edge flange presenting an exterior downwardly andinwardly flaring annular surface, whichflange is adapted to be rotatablyreceived by said container portion when the edge portion of the cover isin serted beneath said inwardly projecting lip, and

securing means on said cover adapted to move cally opposite each other.

into cooperation with said outwardly projecting lip upon rotation ofsaid cover when so received.

12. A pressure cooker according to claim 11 in which the securing meanson the cover is in the form of an outwardly projecting lip adapted to bemoved under the outwardly projecting lip on the container by rotation ofthe cover relative to the latter.

13. A pressure cooker according to claim 11 in which .the inwardlyprojecting lip on the container has its ends substantially diametricallyopposite each other.

14. A pressure cooker according to claim 11 in which the securing meanson the cover is in the form of an outwardly projecting lip adapted to bemoved under the outwardly projecting lip on the container by rotation ofthe cover relative to the latter, the inwardly projecting lip on thecontainer having its ends substantially diametri- WILLIAM A. WELDEN.

REFERENCES CITED The following references are of record in the file'ofthis patent:

UNITED STATES PATENTS

